Muscarinic receptor ligands

ABSTRACT

Described herein are D4 receptor-selective compounds of the general formula I: ##STR1## wherein: A and B are independently selected, optionally substituted, saturated or unsaturated 5- or 6-membered, homo- or heterocyclic rings; 
     X 1  is selected from CH 2 , O, NH, S, C═O, CH--OH, CH--NEt 2 , C═CHCl, C═CHCN, N--C 1-4  alkyl, N-acetyl, SO 2  and SO; 
     X 2  --is selected from N═, CH 2  --, CH═, C(O)--, O--, and S--; 
     n is 1 or 2; and 
     Z is selected from C 1-8  alkyl optionally substituted with a substituent selected from OH, halo, C 1-4  alkyl and C 1-4  alkoxy; 
     and acid addition salts, solvates and hydrates thereof. Their use as ligands for dopamine receptor identification and in a drug screening program, and as pharmaceuticals to treat indications in which the M1/M2 receptor is implicated, such as schizophrenia, is also described.

This is a divisional application of application Ser. No. 08/637,181filed Apr. 24, 1997, now U.S. Pat. No. 5,674,877, which is a division ofapplication Ser. No. 08/358,471 filed Dec. 19, 1994, now U.S. Pat. NO.5,561,127.

This invention relates to compounds that bind selectively to themuscarinic receptors M1 and M2, to the preparation of such compounds andto the use of such compounds for therapeutic and drug screeningpurposes.

BACKGROUND OF THE INVENTION

Among the neuronal and peripheral cell receptors that bind theneurotransmitter acetylcholine (ACh), are the muscarinic receptors.There are reportedly five subtypes classified as M1 through M5, of whichthe M1 and M2 have been implicated in the etiology of such medicalconditions as Parkinson's disease, cardiac disorders andgastrointestinal disorders. It has been suggested that compounds capableof interfering with the action of acetylcholine at these receptors,would be useful to treat these conditions. However, the tendency forligands to bind indiscriminately to various other receptor types, suchas serotonin and dopamine receptors has made difficult the developmentof drugs that are muscarinic M1/M2 receptor-selective. It wouldnevertheless be desirable to provide such a compound, particularly sothat side effects are minimized during treatment of the conditions notedabove.

It is an object of the present invention to provied a compound havingmuscarinic M1/M2 receptor affinity.

It is an object of the present invention to provide a compound having animproved muscarinic M1/M2 receptor selectivity profile.

It is a further object of the present invention to provide apharmaceutical composition comprising a compound of the presentinvention, as active ingredient.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided acompound of Formula I: ##STR2## wherein:

A and B are independently selected, optionally substituted, saturated orunsaturated 5- or 6-membered, homo- or heterocyclic rings;

X₁ is selected from CH₂, O, NH, S, C═O, CH--OH, CH--NEt₂, C═CHCl,C═CHCN, N--C₁₋₄ alkyl, N-acetyl, SO₂ and SO;

X₂ --is selected from N═, CH₂ --, CH═, C(O)--, O--, and S--;

n is 1 or 2; and

Z is selected from C₁₋₆ alkyl optionally substituted with a substituentselected from OH, halo, C₁₋₄ alkyl and C₁₋₄ alkoxy;

and acid addition salts, solvates and hydrates thereof.

According to another aspect of the invention, there is provided apharmaceutical composition comprising a compound of Formula I and apharmaceutically acceptable carrier.

In a further aspect of the invention, there is provided an analyticalmethod in which a compound of the invention is used to distinguishmuscarinic M1/M2 receptors from serotonin receptors such as 5-HT2 and/orfrom dopamine receptors such as the D2 and D4 sub-types.

These and other aspects of the present invention are now described ingreater detail hereinbelow.

DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS

The invention relates to compounds that bind the muscarinic M1/M2receptor in a selective manner, relative to serotonin 5-HT2 and/ordopamine D2 and D4 receptors. In accordance with one of its aspects, thepresent invention accordingly provides compounds that conform to FormulaI: ##STR3##

In embodiments of the invention, Z is selected from C₁₋₆ alkyloptionally substituted with a substituent selected from OH, halo, C₁₋₄alkyl, C₁₋₄ alkoxy and aryl. Particular embodiments of the inventioninclude those in which Z is C₁₋₆ alkyl such as methyl, ethyl, linear orbranched propyl, butyl, pentyl and hexyl optionally substituted with anaryl substituent such as phenyl. More particularly Z is selected frommethyl or benzyl. Most particularly, Z is methyl. In other embodimentsof the invention, n is 1 corresponding to the diazabicyclo(2.2.1)heptanering or n is 2 corresponding to the diazabicyclo(2.2.2)octane ring. In aparticular embodiment n is 1.

The tricyclic function to which the diazabicycloheptane ring is coupledcan have various structures and will typically incorporate those foundto be important for serotonin 5-HT2 receptor binding. Rings A and B areselected, according to embodiments of the invention, from benzene,pyridine, pyrimidine, pyrazine, pyridazine, pyrole, imidazole, triazole,pyrazole, thiophene, thiazole, furan and pyran. In a particularembodiment, ring A is selected from benzene and pyridine and ring B isselected from benzene, pyridine, pyrimidine, pyrazine, pyridazine,pyrole, imidazole, triazole, pyrazole, thiophene, thiazole, furan andpyran; and is particularly selected from benzene and pyridine. Inspecific embodiments of the invention, both rings A and B are benzene.It is to be appreciated that when rings A and B are heterocycles, theheteroatoms are shared with the central seven membered ring only whenthe shared heteroatom is N. Such tricycles are within the scope of theFormula I; one embodiment of which is described by Lednicer et al in TheOrganic Chemistry of Drug Synthesis, (1992, John Wiley & Sons Inc., NewYork) wherein ring B is imidazole that is fused to a thiazepine at oneof the imidazole nitrogen atoms.

One or both rings A and B may be substituted with from 1 to 3, usually 1or 2, substituents. When substituted, the substituents are selected fromhydroxyl, halo, C₁₋₄ alkyl, amino, nitro, cyano, halo-substituted C₁₋₄alkyl, C₁₋₄ alkoxy, halo-substituted C₁₋₄ alkoxy, C₁₋₄ alkoxycarbonyl,C₁₋₄ acyl, halo-substituted C₁₋₄ acyl, cyclo-C₃₋₇ alkyl, thio-C₁₋₄alkylene, C₁₋₄ alkylthio, halo-substituted C₁₋₄ alkylthio, cyanothio,tetrazolyl, N-piperidinyl, N-piperazinyl, N-morpholinyl, acetamido, C₁₋₄alkylsulfonyl, halosulfonyl, halo-substituted C₁₋₄ alkylsulfonyl, C₁₋₄alkylsulfoxyl, sulfonamido, C₁₋₄ alkylseleno, and OSO₃ H.

Substitution sites on rings A and B will be limited in practice to thecarbon atoms on the ring that are not shared with the central sevenmembered ring. For example, a benzene ring can accomodate up to 4substituents; pyridine, and pyran, rings can accomodate up to 3substituents; pyrimidine, pyrazine, pyridazine, pyrole, furan andthiophene rings can accomodate up to 2 substituents; imidazole, pyrazoleand thiazole rings can accomodate only 1 substituent; and a triazolering can accomodate no substituents. It is also to be understood thatrings A and B may incorporate substituents at nitrogen atoms on the ringthat are not shared with the central seven membered ring. For examplethe NH member of an imidazole ring may be substituted. In particularembodiments, rings A and B are substituted with from 1 to 2 substituentsselected from chloro, fluoro, methyl, trifluoromethyl, methoxy, nitro,cyano and methylthio. In particularly preferred embodiments ring A isbenzene substituted with 1 or 2 substituents selected from chloro,methyl, nitro and cyano and ring B is benzene substituted with 1 or 2substituents selected from chloro, methoxy, trifluoromethyl and nitro.

In the central, 7-membered ring of the tricycle, X₁ may be any one ofCH₂, O, NH, S, C═O, CH--OH, CH--N(C₁₋₄ alkyl)₂, C═CHCl, C═CHCN, N--C₁₋₄alkyl, N-acetyl, SO₂ and SO, while X₂ --may be any one of N═, CH₂ --,CH═, C(O)--, O--, and S--. In a particular embodiment of the invention,X₁ is O, S or NH. In another embodiment, X₂ --is N═ or CH═. In aparticularly preferred embodiment, X₁ is O, S or NH and X₂ --is N═ orCH═. In specific embodiments X₁ and X₂ --are selected to form a sevenmembered ring selected from oxazepine, diazepine, thiazepine andthiepine. In preferred embodiments X₁ and X₂ --together with rings A andB are selected to form a tricycle that is selected from 5H-dibenzo b,e!1,4!diazepine that is optionally choloro substituted, for example7,8-dichloro; and dibenz b,f! 1,4!oxazepine that is optionally chlorosubstituted, for example 8-chloro.

In a particular embodiment of the invention, there are providedcompounds of formula (I) that bind to muscarinic M1/M2 receptors,including:

11 -(2-benzyl-2,5-diazabicyclo(2.2.1)hept-5-yl)-dibenz b,f!1,4!oxazepine

8-chloro-11-(2-methyl-2,5-diazabicyclo(2.2.1)hept-5-yl)-dibenz b,f!1,4!oxazepine; and

7,8-dichloro-11-(2-methyl-2,5-diazabicyclo(2.2.1)hept-5-yl)-dibenzo b,e!1,4!diazepine.

In a more preferred embodiment, there are provided compounds of formula(I) that bind to muscarinic M1/M2 receptors in a selective mannerrelative to the serotonin 5-HT2 and dopamine D2 and D4 receptors,including:

8-chloro-11-(2-methyl-2,5-diazabicyclo(2.2.1)hept-5-yl)-dibenz b,f!1,4!oxazepine; and

7,8-dichloro-11-(2-methyl-2,5-diazabicyclo(2.2.1)hept-5-yl)-dibenzo b,e!1,4!diazepine.

Acid addition salts of the compound of Formula I include for examplethose formed with inorganic acids e.g. hydrochloric, sulphuric orphosphoric acids and organic acids e.g. succinic, maleic, acetic orfumaric acid. Other non-pharmaceutically acceptable salts e.g. oxalatesmay be used for example in the isolation of compounds of Formula I forligand use, or for subsequent conversion to a pharmaceuticallyacceptable acid addition salt. Also included within the scope of theinvention are solvates and hydrates of the invention.

The conversion of a given compound salt to a desired compound salt isachieved by applying standard techniques, in which an aqueous solutionof the given salt is treated with a solution of base e.g. sodiumcarbonate or potassium hydroxide, to liberate the free base which isthen extracted into an appropriate solvent, such as ether. The free baseis then separated from the aqueous portion, dried, and treated with therequisite acid to give the desired salt.

It will be appreciated that certain compounds of Formula I may containan asymmetric centre. Such compounds will exist as two (or more) opticalisomers (enantiomers). Both the pure enantiomers and the racemicmixtures (50% of each enantiomer), as well as unequal mixtures of thetwo, are included within the scope of the present invention. Further,all diastereomeric forms possible (pure enantiomers and mixturesthereof) are within the scope of the invention.

The compounds of the present invention can be prepared by processesanalogous to those known in the art. The present invention thereforeprovides, in a further aspect, a process for the preparation of acompound of Formula I or a salt, solvate or hydrate thereof, whichcomprises the step of coupling a reagent of Formula A: ##STR4## with areagent of Formula B: ##STR5## in the presence of diisopropylethylamine(DIEA) or 1,8-diazabicyclo(5.4.0)-undec-7-ene (DBU) in acetonitrile.

The iminochloride, reagent (A), can be obtained commercially or can besynthesized using established techniques, for example, by treating thecorresponding lactam (or ketone) (reagent Q) with PCl₅. Reagent Q mayitself be commercially available or synthesized. For example, when X₁ isNH and X₂ --is N═ (a diazepine), reagent (Q) may be prepared accordingto the procedures described by Giani et al (Synthesis, 1985, 550) byrefluxing equimolar amounts of 2-chlorobenzoic acid, o-phenylenediamineand powdered copper in chlorobenzene. The following is a schematicrepresentation of the reaction to obtain the diazepine form of reagent(Q): ##STR6## When X₁ is O and X₂ --is N═ (an oxazepine), reagent (Q)may be prepared according to the procedures described by Klunder (J.Med. Chem. 1992, 35:1887) by condensation of a 2-aminophenol with2-chloro-5-nitrobenzoyl chloride in THF to afford the correspondingcarboxamide followed by refluxing with NaOH for ring closure. Thefollowing is a schematic representation of the steps to obtain theoxazepine form of reagent (Q): ##STR7##

The thiepine form of reagent (Q), i.e. when X₁ is S and X₂ --is CH═, maybe prepared according to the procedures described by Sindelar et al(Collect. Czech. Chem. Commun, 1983, 48(4):1187). When reagent (Q) is anoxepine i.e. when X₁ is O and X₂ --is CH₂ --, it may be prepared in themanner reported by Harris et al (J. Med. Chem., 1982, 25(7):855); andthe corresponding cycloheptene reagent (Q) i.e. when X₁ and X₂₋₋ areboth CH₂, may be prepared as reported by De Paulis et al (J. Med. Chem.1981, 24(9):1021). The thiazepine reagent (Q) may be prepared in a fourstep process starting from 1-bromo-2-nitrobenzene and methylthiosalicylate. The steps involve coupling; reduction of the nitrogroup; hydrolysis of the ester group; and finally ring closure.

Reagents of Formula B are commercially available or else can besynthesized using established synthetic techniques from startingmaterials that are commercially available.

In another embodiment of the invention, the compound is provided inlabelled form, such as radiolabelled form e.g. labelled by incorporationwithin its structure of ³ H or ¹⁴ C or by conjugation to ¹²⁵ I. Suchradiolabelled forms can be used to directly to distinguish muscarinicreceptors from 5-HT2 and dopamine D4 and D2 receptors. This can beachieved by incubating preparations of the muscarinic receptor and the5-HT2, D4 and D2 receptors with a radiolabelled muscarinic selectivecompound of the invention and then incubating the resulting preparation.The muscarinic, 5-HT2 and dopamine receptors are then distinguished bydetermining the difference in membrane-bound radioactivity, with themuscarinic receptor exhibiting greater radioactivity, i.e. moreradiolabelled compound bound. Furthermore, radiolabelled forms of thepresent compounds can be exploited to screen for more potent muscarinicligands, by determining the ability of the test ligand to displace theradiolabelled compound of the present invention.

The binding profile of the present compounds indicates their utility aspharmaceuticals useful for the treatment of various conditions in whichthe use of a muscarinic receptor ligand is indicated, such as for thetreatment of anxiety and schizophrenia.

For use in medicine, the compounds of the present invention are usuallyadministered in a standard pharmaceutical composition. The presentinvention therefore provides, in a further aspect, pharmaceuticalcompositions comprising an effective amount of a compound of Formula Ior a pharmaceutically acceptable salt, solvate or hydrate thereof and apharmaceutically acceptable carrier.

The compounds of the present invention may be administered by aconvenient route, for example by oral, parenteral, buccal, sublingual,nasal, rectal or transdermal administration and the pharmaceuticalcompositions formulated accordingly.

The compounds and their pharmaceutically acceptable salts which areactive when given orally can be formulated as liquids, for examplesyrups, suspensions or emulsions, tablets, capsules and lozenges.

A liquid formulation will generally consist of a suspension or solutionof the compound or pharmaceutically acceptable salt in a suitablepharmaceutical liquid carrier for example, ethanol, glycerine,non-aqueous solvent, for example polyethylene glycol, oils, or waterwith a suspending agent, preservative, flavouring or colouring agent.

A composition in the form of a tablet can be prepared using any suitablepharmaceutical carrier routinely used for preparing solid formulations.Examples of such carriers include magnesium stearate, starch, lactose,sucrose and cellulose.

A composition in the form of a capsule can be prepared using routineencapsulation procedures. For example, pellets containing the activeingredient can be prepared using standard carriers and then filled intohard gelatin capsule; alternatively, a dispersion or suspension can beprepared using any suitable pharmaceutical carrier, for example aqueousgums, celluloses, silicates or oils and the dispersion or suspensionfilled into a soft gelatin capsule.

Typical parenteral compositions consist of a solution or suspension ofthe compound or pharmaceutically acceptable salt in a sterile aqueouscarrier or parenterally acceptable oil, for example polyethylene glycol,polyvinyl pyrrolidone, lecithin, arachis oil or sesame oil.Alternatively, the solution can be lyophilized and then reconstitutedwith a suitable solvent just prior to administration.

Compositions for nasal administration may conveniently be formulated asaerosols, drops, gels and powders. Aerosol formulations typicallycomprise a solution or fine suspension of the active substance in aphysiologically acceptable aqueous or non-aqueous solvent and areusually presented in single or multidose quantities in sterile form in asealed container, which can take the form of a cartridge or refill foruse with an atomising device. Alternatively, the sealed container may bea unitary dispensing device such as a single dose nasal inhaler or anaerosol dispenser fitted with a metering valve which is intended fordisposal after use. Where the dosage form comprises an aerosoldispenser, it will contain a propellant which can be a compressed gassuch as compressed air or an organic propellant such asflurochlorohydrocarbon. The aerosol dosage forms can also take the formof a pump-atomizer.

Compositions suitable for buccal or sublingual administration includetablets, lozenges, and pastilles, wherein the active ingredient isformulated with a carrier such as sugar, acacia, tragacanth, or gelatinand glycerine.

Compositions for rectal administration are conveniently in the form ofsuppositories containing a conventional suppository base such as cocoabutter.

Preferably, the composition is in unit dose form such as a tablet,capsule or ampoule. Suitable unit doses i.e. therapeutically effectiveamounts; can be determined during clinical trials designed appropriatelyfor each of the conditions for which administration of a chosen compoundis indicated and will of course vary depending on the desired clinicalendpoint. It is anticipated that dosage sizes appropriate foradministering the compounds of the examples will be in the range fromabout 0.1 to about 500 mg/kg body weight eg. 0.1 to about 100 mg/kg bodyweight, and will be administered in a frequency appropriate for initialand maintenance treatments.

EXAMPLE 1 Preparation of Intermediate(1S,4S)-2-Methyl-2,5-diazabicyclo(2.2.1)heptane

(1S,4S)-2-Benzyl-2,5-diazabicyclo(2.2. 1)heptane dihydrobromide(Medinger & Sohne Sanochemica-Gruppe, Austria, M-P701, 5.0 g, 0.0143mol) was stirred for 10 min in a solution of 1N KOH (0.029 mol). Theliberated base was extracted with CHCl₃ ; dried (K₂ CO₃) and evaporatedto dryness in vacuo; yield 2.4 g, (88%).

EXAMPLE 2 Preparation of Intermediate(1S,4S)-5-methyl-2,5-diazabicyclo(2.2.1)heptane

To a solution of (1S,4S)-2-Benzyl-2,5-diazabicyclo(2.2.1)heptane (2.4 g,0.013 mol) in dry CH₂ Cl₂, triethylamine (8.7 mL, 0.063 mol) was addedand upon cooling of the solution to 0° C. ethyl chloroformate (1.8 mL,0.019 mol) was added. The mixture was warmed to room temperature andmixed for 2 hrs. The reaction mixture was diluted with ice cold water(30 mL) and extracted with CH₂ Cl₂. The combined organic phases weredried (K₂ CO₃) and concentrated in vacuo. The product(1S,2S)-2-benzyl-5-ethoxycarbonyl-2,5-diazabicyclo(2.2.1)heptane wasdried in a desiccator over K₂ CO₃.

To a solution of(1S,4S)-2-benzyl-5-ethoxycarbonyl-2,5-diazabicyclo(2.2.1)heptane (3.3 g,0.013 mol) in THF at -10° C., was added dropwise 1M LiAlH₄ in ether(26.3 mL, 0.026 mol). The reaction mixture was slowly warmed to roomtemperature and mixed overnight. Upon cooling to 0° C., 4 mL of 95%THF:H₂ O was slowly added followed by 4 mL of H₂ O. The mixture wasdiluted with NH₄ OH (40 mL), filtered through a celite pad andconcentrated in vacuo. The remaining NH₄ OH solution was further dilutedwith NH₄ OH (15 mL) and extracted with CH₂ Cl₂. The combined organicphases were dried (K₂ CO₃) and concentrated in vacuo to yield(1S,4S)-2-benzyl-5-methyl-2,5diazabicyclo(2.2.1)heptane (2.2 g, 86%).

To a solution of (1S,4S)-2-benzyl-5-methyl-2,5diazabicyclo(2.2.1)heptane(2.2 g, 0.011 mol) in methanol, was added Pd(OH)₂ (20% w/w) and themixture was stirred overnight under H₂. The reaction mixture wasfiltered through a celite pad and concentrated in vacuo. The product(1S,4S)-5-methyl-2,5-diazabicyclo(2.2.1)heptane, an oil was stored withKOH pellets under argon at -20° C. in the dark; yield 1.2 g, (98%).

EXAMPLE 3 Preparation of Intermediate 8-chloro-11-oxo-dibenz b,f!1,4!thiazepine

A solution of NaH (1.1 g, 0.04 mol) in dry THF (20 mL) was cooled to 0°C. To this mixture methyl thiosalicylate (5.1 mL, 0.036 mol) was addeddropwise via syringe. The reaction mixture was warmed to roomtemperature to ensure completion of the reaction. The solution wascooled to 0° C. and 2,5-dichloronitrobenzene (7.0 g, 0.036 mol) wasadded dropwise in THF (20 mL). The reaction was stirred at 0° C. for 30min then stirred at room temperature for 4 hrs. The reaction wasquenched with 5 mL ice cold water and then diluted with EtOAc (300 mL).The phases were separated and the organic phase was washed with sat.NaHCO₃, water and brine. The organic phase was dried (MgSO₄) andconcentrated in vacuo. Recrystallization was done in CHCl₃ and Et₂ O; toyield 2-nitro-4-chloro-2'-methoxycarbonyl-diphenylsulfide 10.9 g, (93%).

To a solution of 2-nitro-4-chloro-2'-methoxycarbonyl-diphenylsulfide(10.3 g, 0.032 mol) in 78% ethanol (200 mL) a solution of CaCl₂ (2.3 g,0.019 mol) in 4 mL water was added. Zn dust (68.9 g, 1.05 mol) was addedand the mixture was refluxed for 3 hrs. The hot mixture was filteredthrough a celite pad and washed with hot ethanol. The filtrate wasconcentrated in vacuo to obtain the solid2-amino-4-chloro-2'-methoxycarbonyl-diphenylsulfide; yield 10.01 g,(98%).

To a solution of 2-amino-4-chloro-2'-methoxycarbonyl-diphenylsulfide(9.4 g, 0.032 mol) in ethanol, was added 1N KOH (67 mL, 0.067 mol) andthe mixture refluxed for 2 hrs. The ethanol was removed and the solutionwas cooled to 0° C. The product2-amino-4-chloro-2'-carboxyl-diphenylsulfide was precipitated bydropwise addition of conc. HCl to pH3. The precipitate was filtered andcollected and dried; yield 8.5 g, (95%).

To a solution of 2-amino-4-chloro-2'-carboxyl-diphenylsulfide (8.4 g,0.03 mol) in dry CH₂ Cl₂, was added 4-dimethylaminopyridine (1.2 g,0.009 mol) and 1-(3- dimethylaminopropyl)-3-ethylcarbodiimidehydrochloride (10.1 g, 0.053 mol) and stirred at room temperatureovernight. The solution was concentrated in vacuo, then diluted withwater (200 mL) and ether (50 mL) and placed in refrigerator. Theprecipitate 8-chloro-11-oxo-dibenz b,f! 1,4!thiazepine was filtered anddried under vacuum; yield 7.2 g, (92%).

In a like manner, the intermediate 11-oxo-dibenz b,f! 1,4!thiazepine wasprepared starting from 1-bromo-2-nitrobenzene

EXAMPLE 4 Preparation of8-chloro-11-(2-methyl-2,5-diazabicyclo(2.2.1)hept-5-yl)-dibenzo b,f!1,4!thiazepine

To a solution of 8-chloro-11-oxo-dibenz b,f! 1,4!thiazepine (0.3 g,0.0011 mol) in dry toluene (10 mL), was added PCl₅ (0.27 g, 0.0013 mol)in one portion and then refluxed for 4 hrs. The toluene was removed invacuo and the imino chloride was dried under vacuum.

To a solution of imino chloride (0.32 g, 0.0011 mol) in dry acetonitrile(20 mL), was added diisopropylethylamine (1.12 mL, 0.006 mol) and(1S,2S)-2-methyl-2,5-diazabicyclo(2.2.1)heptane (0.36 g, 0.003 mol) viasyringe. The mixture was refluxed for 6 hrs. The acetonitrile wasevaporated off in vacuo and the resulting oil was diluted in water andextracted with CH₂ Cl₂. To the resulting CH₂ Cl₂ phase 1N HCl (20 mL)was added. The aqueous phase was washed with CH₂ Cl₂, basified with NH₄OH to pH 9-10 and extracted with CH₂ Cl₂. The resulting organic phasewas dried (MgSO₄) and concentrated in vacuo. The crude material waschromatographed (CHCl₃ :MeOH, 95:5) to give8-chloro-11-(2-methyl-2,5-diazabicyclo(2.2.1)hept-5-yl)-dibenzo b,f!1,4!thiazepine (0.26 g, 65%, mp 62-64° C.).

In a like manner the following compounds were prepared:

a) 11-(2-methyl-2,5-diazabicyclo(2.2.1)hept-5-yl)-dibenzo b,f!1,4!thiazepine (yield 40%, mp 60°-61° C.) from 11-oxo-dibenzo b,f!1,4!thiazepine;

b) 8-chloro-11-(2-methyl-2,5-diazabicyclo(2.2.1)hept-5-yl)-dibenz b,f!1,4!oxazepine (yield 53%, mp 58°-60° C.) from 8-chloro-11-oxo-dibenzb,f! 1,4!oxazepine prepared according to the procedures described byCoyne et al, in J. Med. Chem., 1967, 10:541. Briefly, this entailedcoupling potassium salicylaldehyde with 2,5- dichloronitrobenzene,followed by oxidation to carboxylic acid, reduction of nitro, andfinally ring closure, to yield the desired 8-chloro compound (m.p.256°-258° C.); and

EXAMPLE 5 Preparation of11-(2-benzyl-2,5-diazabicyclo(2.2.1)hept-5-yl)-dibenz b,f! 1,4!oxazepine

To a solution of 11-oxo-dibenz b,f! 1,4!oxazepine (Aldrich) (0.149 g,0.0007 mol) in dry toluene (10 mL), was added(1S,4S)-2-benzyl-2,5-diazabicyclo(2.2.1)heptane (0.54 g, 0.003 mol) andTiCl₄ (0.75 mL, 0.0008 mol) via syringe. The mixture was stirred at roomtemperature for 30 min then refluxed for 5 hrs. The reaction mixture wascooled and dumped into conc. NH₄ OH and extracted with CHCl₃. Thecombined organic phases were dried (MgSO₄) and concentrated in vacuo.The crude material was chromatographed (hexane:EtOAc, 1:1) to give11-(2-benzyl-2,5-diazabicyclo(2.2.1) hept-5-yl)-dibenz b,f!1,4!oxazepine (yield 0.1319, mp 70°-72° C.).

In a like manner7,8-dichloro-11-(2-methyl-2,5-diazabicyclo(2.2.1)hept-5-yl)-dibenzo b,e!1,4!diazepine (yield 10%, mp 70°-72° C.) was prepared from7,8-chloro-11-oxodibenzo b,e! 1,4!diazepine which was prepared accordingto the procedures described by Giani et al, in Synthesis 550, (1985).

EXAMPLE 6 Muscarinic Receptor Binding Assay

M1/M2 receptor-binding affinities of the compounds of examples 4 and 5were evaluated according to their ability to reduce binding of tritiatedRS (±) quinuclidinyl benzylate (³ H-QNB), a muscarinic receptorantagonist. The potency of the test compound to reduce ³ H-QNB bindingdirectly is correlated to its binding affinity for the receptor.

M1/M2 Receptor Preparation

Rat frontal cortex tissue was initially prepared by AnalyticalBiological Services by the following steps: homogenizing in 10 volumesof 0.32M sucrose at 4° C.; centrifuging at 900×g for 10 minutes;centrifuging supernatant at 48,000×g for 20 minutes; suspending pelletin 20 volumes 50 mM Tris HCl, pH 7.7 containing 5 mM calcium chloride;incubating at 37° C. for 30 minutes; centrifuging at 48,000×g for 30minutes; suspending pellets in 2 volumes of buffer and storing in 15 mLaliquots at -70° C. On day of study, the tissues were thawed on ice for20 minutes. The tissues were pooled together and resuspended in 30 mLincubation buffer (40.5 mM Na₂ HPO₄, 9.5 mM KH₂ PO₄, 50 μM ascorbicacid) pH 7.4 at 4° C. The tissues were then homogenized with aKinematica CH-6010 Kriens-LU homogenizer for 15 seconds, setting 6. Thehomogenate was centrifuged at 20,000 rpm for 30 minutes at 4° C.,Beckman SW28 rotor. The entire pellet was resuspended in 10 mL ofincubation buffer (40.5 mM Na₂ HPO₄, 9.5 mM KH₂ PO₄, 50 μM ascorbicacid, pH 7.4) and homogenized with a cold Douce homogenizer, 10 strokes,10 mL buffer, at 4° C. The protein concentration was determined usingthe Pierce BCA Assay, adding 10 μL of membrane preparation per sample,in triplicate. Membrane preparations were made in incubation buffer.

Total ³ H-QNB Binding

The incubation was started in 12×75 mm borosilicate glass tubes by theaddition of 1000 μL membrane homogenate (100 μg protein) to a solutionof 800 μL incubation buffer (40.5 μM Na₂ HPO₄, 9.5 mM KH₂ PO₄, 50 μMascorbic acid, pH 7.4) and 200 μL ³ H-QNB (0.126 nM final concentration,86 Ci/mmol, NEN Research Products). The tubes were vortexed and placedin a 32° C. water bath for 60 minutes. The binding reaction was stoppedby immersing the tubes in an ice water bath for 5 minutes. The sampleswere then filtered under vacuum over glass fibre (Whatman GF/B) soakedin 0.3% polyethylenimine (PEI) in 40.5 mM Na₂ PO₄, 9.5 mM KH₂ PO₄ buffer(pH 7.4) for at least 2 hours and then washed 3 times with 5 mL ice cold40.5 mM Na₂ HPO₄, 9.5 mM KH₂ PO₄ buffer (pH 7.4) using a Brandell CellHarvester. Individual filter disks were put in scintillation vials(Biovials, Beckman). Ready Protein Plus liquid scintillant (5 mL,Beckman) was added and the vials counted by liquid scintillationspectrophotometry (Beckman LSC 6500) after equilibrating for three hoursat room temperature to give total binding (B_(T)).

Non-Specific Binding

The incubation was started in 12×75 mm borosilicate glass tubes by theaddition of 1000 μL membrane homogenate (100 μg protein) to a solutionof 800 μL (1 μM final conc.) atropine sulphate (1 mM stock dissolved inwater, diluted in incubation buffer, Research Biochemicals), and 200 μL³ H-QNB (0.126 nM final concentration, 86 Ci/mmol, NEN ResearchProducts). The tubes were vortexed and placed in a 32° C. water bath for60 minutes. The binding reaction was stopped by immersing the tubes inan ice water bath for 5 minutes. The samples were then filtered andcounted using the same procedure as in the total binding assay describedabove to give the non-specific binding value (NSB).

Displacement Binding

The incubation was started in 12×75 mm borosilicate glass tubes by theaddition of 1000 μL membrane homogenate (100 μg protein) to a solutionof 800 μL test compound (1 mM stock dissolved in DMSO, stored at -20° C.in polypropylene cryogenic storage vials and diluted in incubationbuffer), and 200 μL ³ H-QNB (0.126 nM final concentration, 86 Ci/mmol,NEN Research Products). The tubes were vortexed and placed in a 32° C.water bath for 60 minutes. The binding reaction was stopped by immersingthe tubes in an ice water bath for 5 minutes. The samples were thenfiltered and counted using the same procedure as in the total bindingassay described above to give the displacement binding value (B_(D)).

Calculations

The test compounds were initially assayed at 1 and 0.1 μM and then at arange of concentrations chosen such that the middle dose would causeabout 50% inhibition of ³ H-QNB binding. Specific binding in the absenceof test compound (B_(O)) was the difference of total binding (B_(T))minus non-specific binding (NSB) and similarly specific binding (in thepresence of test compound) (B) was the difference of displacementbinding (B_(D)) minus non-specific binding (NSB). IC₅₀ was determinedfrom an inhibition response curve, logit-log plot of %B/B_(O) vsconcentration of test compound.

Ki was calculated by the Cheng and Prustoff transformation:

    Ki=IC.sub.50 /(1+ L!/K.sub.D)

where L! is the concentration of ³ H-QNB used in the assay and K_(D) isthe dissociation constant of ³ H-QNB determined independently under thesame binding conditions.

EXAMPLE 7 5-HT2 Receptor Binding Assay

5-HT2 receptor-binding affinities of the compounds of examples 4 and 5were evaluated according to their ability to reduce binding of tritiatedketanserin, a serotonin receptor antagonist. The potency of the testcompound to reduce ³ H-ketanserin binding is directly correlated to itsbinding affinity for the receptor.

5-HT2 Receptor Preparation

Rat frontal cortex tissue was initially prepared by AnalyticalBiological Services by the following steps: homogenizing in 10 volumesof 0.32M sucrose at 4° C.; centrifuging at 900×g for 10 minutes;centrifuging supernatant at 48,000×g for 20 minutes; suspending pelletin 20 volumes 50 mM Tris HCl, pH 7.7 containing 5 mM calcium chloride;incubating at 37° C. for 30 minutes; centrifuging at 48,000×g for 30minutes; suspending pellets in 2 volumes of buffer and storing in 15 mLaliquots at -70° C. On day of study, tissues were thawed on ice for 20minutes. The entire pellet was resuspended in 5 mL of buffer (50 mMTris, 0.5 mM EDTA, 10 mM MgSO₄, 10 uM pargyline, 0.1% ascorbic acid, pH7.4) at 4° C. and sonicated with a Sonifier Cell Disrupter 350 at 8microtip units for 6 seconds power 80. The protein concentration wasdetermined using the Pierce BCA Assay, adding 1 μL of membranepreparation per sample, in triplicate. Membrane preparations were madein incubation buffer.

Total ³ H-ketanserin Binding

The incubation was started in 12×75 mm polypropylene glass tubes by theaddition of 400 μL membrane preparation (100 μg protein) to a solutionof 500 μL incubation buffer (50 mM Tris, 0.5 mM EDTA, 10 mM MgSO₄, 10 μMpargyline, 0.1% ascorbic acid, pH 7.4) and 100 μL ³ H-ketanserin (1 nMfinal concentration, 85 Ci/mmol, NEN Research Products). The tubes werevortexed and incubated at room temperature for 30 minutes. The bindingreaction was stopped by filtering. The samples were filtered undervacuum over glass fibre filters (Whatman GF/B) soaked in 0.3%polyethylenimine (PEI) in 50 mM Tris (pH 7.4) for 2 hours and thenwashed 3 times with 5 mL ice cold 50 mM Tris buffer (pH 7.4) using aBrandell Cell Harvester. Individual filter disks were put inscintilation vials (Biovials, Beckman). Ready Protein Plus liquidscintilant (5 mL, from Beckman) was added and the vials were counted byliquid scintillation spectrophotometry (Beckman LSC 6500) afterequilibrating for three hours at room temperature to give total bidning(B_(T)).

Non-Specific Binding

The incubation was started in 12×75 mm polypropylene tubes by theaddition of 400 μL membrane preparation (100 μg protein) to a solutionof 500 μL methysergide (30 μM final conc. from 1 mM stock dissolved inDMSO and diluted in incubation buffer, Research Biochemicals Inc.) and100 μL ³ H-ketanserin (1 nM final concentration, 85 Ci/mmol, NENResearch Products). The tubes were vortexed and incubated at roomtemperature for 30 minutes. The binding reaction was stopped byfiltering. The filters were washed and counted using the same procedureas in the total binding assay described above to give the non-specificbinding value (NSB).

Displacement Binding

The incubation was started in 12×75 mm polypropylene tubes by theaddition of 400 μL membrane preparation (100 μg protein) to a solutionof 500 μL test compound (initially 1 and 0.1M final conc. in incubationbuffer) and 100 μL ³ H-ketanserin (1 nM final concentration, 85 Ci/mmol,NEN Research Products). The tubes were vortexed and incubated at roomtemperature for 30 minutes. The binding reaction was stopped byfiltering. The filters were washed and counted using the same procedureas in the total binding assay described above to give the displacementbinding value (B_(D)).

Calculations

The test compounds were initially assayed at 1 and 0.1 μM and then at arange of concentrations chosen such that the middle dose would causeabout 50% inhibition of ³ H-ketanserin binding. Specific binding in theabsence of test compound (B_(O)) was the difference of total binding(B_(T)) minus non-specific binding (NSB) and similarly specific binding(in the presence of test compound) (B) was the difference ofdisplacement binding (B_(D)) minus non-specific binding (NSB). IC₅₀ wasdetermined from an inhibition response curve, logit-log plot of %B/B_(O)vs concentration of test compound.

Ki was calculated by the Cheng and Prustoff transformation:

    Ki=IC.sub.50 /(1+ L!/K.sub.D)

where L! is the concentration of ³ H-ketanserin used in the assay andK_(D) is the dissociation constant of ³ H-ketanserin determinedindependently under the same binding conditions.

EXAMPLE 8 Dopamine Receptor Binding Assay

D2 and D4 receptor-binding affinities of the compounds of examples 1 and2 were evaluated according to their ability to reduce binding of ³H-spiperone as compared to the reference compound clozapine. The potencyof the test compound to reduce ³ H-spiperone binding directly correlatedto its binding affinity for the receptor.

D4 Receptor Preparation

HEK 298 (human embryonic kidney) cells stably transfected with human D4receptor (D4.2 sub-type) were grown in NUNC cell factories for 5 days(75% confluency) without a media change and removed with versene(approximately 19 mg of cells per cell factory tray). The cells werethen centrifuged in a Sorval centrifuge for 10 minutes, 5000 rpm (GS3rotor) and the pellets quickly frozen in liquid nitrogen and stored at-80° C. until used in binding assay. When used in the assay, cells werethawed on ice for 20 minutes and then 10 mL of incubation buffer (50 mMTris, 1 mM EDTA, 4 mM MgCl₂, 5 mM KCl, 1.5 mM CaCl₂, 120 mM NaCl, pH7.4)was added. The cells were then vortexed to resuspend pellet andhomogenized with a Kinematica CH-6010 Kriens-LU homogenizer for 15seconds at setting 7. Concentration of receptor protein was determinedusing the Pierce BCA assay.

D2 Receptor Preparation

GH₄ C₁ (rat pituitary) cells stably transfected with the human D2receptor (short isoform) were grown in CO₂ independent media in rollerbottles (1500 cm²) for 10 days. 100 μM ZnSO₄ was added to the cells (theD2 promoter being zinc inducible). After 16 hours, fresh media was addedto allow the cells to recover for 24 hours. The cells were harvestedusing versene and then centrifuged in a Sorval centrifuge for 10minutes, at 5000 rpm (GS3 rotor). Pellets were quickly frozen in liquidnitrogen and stored at -80° C. until used in the binding assays. Whenused in the assay, cells were thawed on ice for 20 minutes. Each rollerbottle produced approximately 72 mg of protein. 10 mL of incubationbuffer was added to the pellets which were then vortexed, resuspendedand homogenized with a Kinematica CH-6010 Kriens-LU homogenizer for 15seconds at setting 7. The receptor protein concentration was determinedusing the Pierce BCA assay.

Total Spiperone Binding Assay

The incubation was started by the addition of 500 μl (50 μg protein)membrane homogenate to a solution of 900 μl incubation buffer and 100 μl(0.25 nM final conc.) ³ H-spiperone (90 Ci/mmol Amersham diluted inborosilicate glass vial) in 12×75 mm polypropylene tubes. The tubes werevortexed and incubated at room temperature for 90 minutes. The bindingreaction was stopped by filtering using a Brandell Cell Harvester. Thesamples were filtered under vacuum over glass fibre filters (WhatmanGF/B) presoaked for 2 hours in 0.3% polyethylenimine (PEI) in 50 mM Trisbuffer (pH7.4). The filters were then washed 3 times with 5 mL ice cold50 mM Tris buffer (pH7.4). Individual filter disks were put inscintillation vials (Biovials, Bechman). Ready Protein Plus liquidscintillant (5 mL, Beckman) was added and the vials counted by liquidscintillation spectrophotometry (Beckman LSC 6500) after equilibratingfor three hours at room temperature to determine total binding (B_(T)).

Non-Specific Binding Assay for D4

The incubation was started by the addition of 500 μl (50 μg protein)membrane homogenate to a solution of 400 μ incubation buffer, 100 μl ³H-spiperone (90 Ci/mmol Amersham diluted in borosilicate glass vial to0.25 nM final conc.) and 500 μl (30 μM final conc.) of fresh dopamine(Research Biochemicals Inc., light protected and dissolved in incubationbuffer) in 12×75 mm polypropylene tubes. The tubes were vortexed andincubated at room temperature for 90 minutes at which time the bindingreaction was stopped by filtering. The filters were washed and countedusing the same procedure as in the total binding assay described aboveto give the non-specific binding value (NSB).

Non-Specific Binding Assay for D2

This assay employed the same procedures as the non-specific bindingassay for D4 with the exception that 2 μM (final conc.) of (-) sulpiride(Research Chemicals Inc.) was used in place of dopamine.

Displacement Binding Assay

The incubation was started by the addition to 12×75 mm polypropylenetubes 500 μl (50 μg protein) membrane homogenate to a solution of 400 μlincubation buffer, 100 μl (0.25 final conc.) ³ H-spiperone (90 Ci/mmol,Amersham, diluted in borosilicate glass vial to) and 500 μl of testcompound that was prepared from 1 mM stock dissolved in DMSO and storedat -20° C. in polypropylene cryogenic storage vials until dilution inincubation buffer in borosilicate glass vials. The tubes were vortexedand incubated at room temperature for 90 minutes at which time thebinding reaction was stopped by filtering. The filters were washed andcounted using the same procedure as in the total binding assay describedabove to give the displacement binding value (B_(D)).

Calculations

The test compounds were initially assayed at 1 and 0.1 μM and then at arange of concentrations chosen such that the middle dose would causeabout 50% inhibition of ³ H-spiperone binding. Specific binding in theabsence of test compound (B_(O)) was the difference of total binding(BT) minus non-specific binding (NSB) and similarly specific binding (inthe presence of test compound) (B) was the difference of displacementbinding (B_(D)) minus non-specific binding (NSB). IC₅₀ was determinedfrom an inhibition response curve, logit-log plot of %B/B_(O) vsconcentration of test compound.

Ki was calculated by the Cheng and Prustoff transformation:

    Ki=IC.sub.50 /(1+ L!/K.sub.D)

where L! is the concentration of ³ H-spiperone used in the assay andK_(D) is the dissociation constant of ³ H-spiperone determinedindependently under the same binding conditions.

Assay results are reported in the following Table:

    __________________________________________________________________________    RECEPTOR AFFINITIES (Ki in nM)                                                COMPOUND    STRUCTURE           M1/M2                                                                             D4 D2 5-HT2                               __________________________________________________________________________    clozapine                                                                                  ##STR8##           16  23 230                                                                              7.5                                 11-(2-benzyl-2,5- diazabicyclo(2.2.1)hept- 5-yl)-dibenz b, f! 1, 4!           oxazepine                                                                                  ##STR9##           882 632                                                                              1333                                                                             3667                                8-chloro-11-(2-methyl- 2,5-diazabicyclo(2.2.1) hept-5-yl)-dibenz b, f! 1,     4! oxazepine                                                                               ##STR10##          28  4769                                                                             4518                                                                             1019                                7,8-dichloro-11-(2- methyl-2,5-diazabicyclo (2.2.1)hept-5-yl)-dibenzo  b,     e! 1, 4!diazepine                                                                          ##STR11##          41  4769                                                                             4711                                                                             1600                                __________________________________________________________________________

We claim:
 1. A compound of Formula I: ##STR12## wherein: A and B arebenzene, unsubstituted or substituted with substituents selectedindependently from hydroxyl, halo, C₁₋₄ alkyl, amino, nitro, cyano,halo-substituted C₁₋₄ alkyl, C₁₋₄ alkoxy, halo-substituted C₁₋₄ alkoxy,C₁₋₄ alkoxycarbonyl, C₁₋₄ alkylC(O)-, cyclo-C₃₋₇ alkyl, thiol-C₁₋₄alkylene, C₁₋₄ alkylthio, halo-substituted C₁₋₄ alkylthio, cyanothio,tetrazolyl, N-piperidinyl, N-piperazinyl, N-morpholinyl, acetamido, C₁₋₄alkylsulfonyl, halo-substituted C₁₋₄ alkylsulfonyl, C₁₋₄ alkylsulfoxyl,sulfonamido, C₁₋₄ alkylseleno, and OSO₃ H;X, is selected from the groupconsisting of NH, N--C₁₋₄ alkyl, and N-acetyl; X₂ --is selected from thegroup consisting of CH₂ --, and CH═ n is 1 or 2; and Z is selected fromC₁₋₆ alkyl optionally substituted with a substituent selected from OH,halo, C₁₋₄ alkyl and C₁₋₄ alkoxy; and acid addition salts, and solvatesthereof.
 2. The compound according to claim 1, wherein A and B aresubstituted with 1 or 2 substituents.
 3. The compound according to claim1, wherein X₁ is NH.
 4. The compound according to claim 1, wherein Z ismethyl.
 5. The compound according to claim 3, wherein Z is methyl.
 6. Apharmaceutical composition, comprising a compound according to claim 1,and a pharmaceutically acceptable carrier.